Tunnel drier



oct. 11, 1927.

W. E. vHAMILTON ET AL TUNNEL DRIER Filed Feb. 15, 1922 Patented Oct. 11, 1927.

nairsr WiLLIAi/i n. HAMILToNjAim ERNEST a. sachant, 'or coraiiiisns, oirio; Annie.

:BAGNALL EXECUTRIX on sainiiniiiisr BAGNALL, DEcEAsED.

y'rUiuNiiL imitan. j

This inventionirelates to a pre-'drying apparatus for use separately orin connection l with rotary driers vor the like, .to utilize general, `to provide theconstruction herein waste heat from other driers, 'furnace/S, 0r steam coils, making a complete pre-drying process `for 'loose material such 4as fullers earth.w The principal object of the inven.

ltion is to provide an. improved, simple `and efficient apparatus of this. kind for drying material. Other objects of the invention are: toprovide 'a continuous drier of this kind; to continuously stir and move` the material dried; to vaporize the moisture and to carry awaygases `from the material to be dried; to seal "one, open end of the drier against the passage of hotair therefrom; l.to provide variable agitating. means; andv in shown and described. n i

In the accompanying drawings, Fig. l is a plan view partly in section of a drier .con-l structed in accordance vwith the4 principlesV of this invention; Fig. Qjis a sideelevation with parts broken away for clearness, ofthe drier illustrated in Fig. 1;.and Fig. 3 is a sectionalview yof the drier. f

This apparatus comprises upper and lower closed troughs, ortunnels in which is operated al conveyor of two strands of chain or cable with yflights attached thereto .ha-.ving Scrapers which keep the material in the tunnels stirred and turned in order to constantly bring the undried material in contact with warm dry air. The bottom of the troughs or any portion thereof may also contain steam pipes or other heating means.

Referring now more particularlyrto the ldrawings,'the upper and lower troughs l and 2 are combined inl a single vstructure closed at one vend to yform the principal part of the,v frame work of the vapparatus and are.' covered to form a closed duct, the bottom of the, upper trough terminating `at a distance from the closed end V3 of the complete hous-y ing to provide a continuous run for apair of chains 4 mounted on sprocket wheels 5 at the ends of the housing so that the *chains can runcontinuously in the upper and 'lower troughs.

The sides of' the troughs yare formed with shoulders or projections 7 for support- Ling the chainse and connecting the chains are flights 8 to each 'of which one or more or any "other'hot vapor.

able manner. These llingers extend .above 'Scrapers 'or lingers 9 are 'secured 'in any/suitgage and stir up material lying at the liot-- tom ofthe troughs, and will alslomo've the materialalong in the troughs. A In .the bottom of the upper trough l are ffm plurality of pipes 'l0 connected at the endsto` headers llfand l2, one or beth'of which `may jbe connected to a source ofsteain supply '.Ihe sprocket wheels '5 at one drier are provided with adjusting `screws 13 by means of which the sprocket wheels may K Vbe moved to tighten or loosenthe chains.

Une end of the drier is preferablyv left open and at this end is 'a Shilling hopperjll and a vapor discharge pipe 15in the upper trough and a discharge spout -16 at 'the "bt-l tom of the lower troughjQ.y

At one side of the drieris a'fan 1.7en-v closedin a housing 1S connected ithrotugli Ethe '75 side of th lower trough 2 and 'having an 'in'- let pipe 19 whichy furnishes a supply of air or other gases preferably heated 'or dry and suitable for drying purposes.` In orderfftjo prevent the escape of the dry gases 'from the lower run of the apparatus, "a plurality of -doors 20 are hinged in the top fof v'the 'lower `run which arefadapted to be'engaged bythe chain flights in passing Iand tofop'en thel `doors in succession, the jdo'ors being so spaced l 'as to form a seal to prevent the rapid escape of the dry gases fromr this end Iof ythe trough. 'ljhe doors are returned to their n'orinal"up right positionby springs or by gravity, and

a similar` arrangement may b'e used at 'anyf point along the conveyor for a lsimilar purpose. y

In 'order to drive the chains 4 the sprockets 5 at one end are mounted onaco'innion shaft 6 andan outside driving gear 2l vmeshes with noy a-gear 22 mounted on lthe shaft 23 of a pul` v -le`y2'4e driven by a belt 25. Also ymounted on this shaft'is a gearcoi'inection 2G with a shaft 27 forl driving the fan v17. In operation, .the driving` means moves 'the upper portion of the Ichain from left to right and the lower runL of the chain in the lopposite direction.

ico

The fan forces air into the lower (Lilosed. trough, which is closed at'one ehd ybyfthe doors 20, s@ that the Aair moves toL theclosed end 3 and thence through the upper v'run in ics the opposite direction until it reaches the opening l5 where it is discharged.

Material to be dried is placed in the hopper 14 and falls to the bottom of the upper trough upon the pipes l() until it reaches the height of the lower side of the flights, or until carried to the right by the scraper fingers. As the pipes 10 are hot, the material is heated sufliciently to prevent the condensation of moisture from the gases passing over it, and by contact with the gases some of the moisture is absorbed and carried off through the discharge. As the conveyor flights pass the material, the scraper lingers stir. and turn'the hotter portionup to the air allowingthe cooler material to fall down in Contact with the hot pipes, thus allowing the material to be alternately heated, eX- posed to the air, and cooled by the evaporation of moisture., During this stirring process` the material is moved slowly alongthe.

trough to the right and when it reaches the end of the upper trough drops to the lower trough or runway where the same stirring process is continued by the upper end of the scraper finger 9, after-the flights of the chain have turned over the sprockets atthe right hand end. y

kAs the material approaches the discharge spout 16, it has lost most of its moisture, but asthe flow of air is in a direction opposite to the travel of the material the air is fresh and dry near the discharge point of the material and hence absorbs the water more completely fromV the material, thus leaving it drier and at a lower temperature than would otherwise bepossible.

Duringthe passage of lmaterial over the hot pipes or the heated trough bottom, any part ofthe material becoming dried also loses weight due to the loss of the contained moisture and thereforey due to its relative lightness has a tendency to rise to the top of the stirred mass of material. As it rises to the top' of the material lying in the trough, it reaches the level of the conveyor flights which at once carry or scrape it forward toward thedischarge, or until it mixes with material drier and lighter than it, and consequently falls again in contact with the heated trough bot-tom while drier material displaced by it is carried by the iights to the discharge spout.

The machine and system is also adapted to the drying of materials that do not permit of `a high heat being used, the drying efl'ect of the system depending upon the absorbtion of moisture from the material to be dried by dry air in close contact with the material at any temperature, the only limiting condition being that the air or other gases used are below their saturation point at the temperature used.

This machine is also adapted to the drying of materials that cannot be subjected to the more severe rolling and mixing process common in rotary driers, or to the drying of highly combustible materials, as no direct heat is necessary in the process nor is the material exposed to contact with fiames'or highly heated surfaces. The machine is especially adapted to use in connection withr rotary or other driers'where a reduction in the moisture in the material makes it more easily handled in the drier, which the crushing or other process `do not require, as it is adaptedto the use of waste heat by radiation, convection or conductiony from such driers,.making eliicient use of gas or liquid of low temperature Vheretofore a complete loss by radiation.

Ve claim:

l. A tunnel vdrierfenclosed at one end having upper and lower trough portions, a pair of endless chains mounted to move in opposite directions in the trough portions, flights f connecting the chains, means adjustable on the flights for engaging material in the different troughs. f u

2. In a drier having upperv and lower runs, an endless conveyor movable oppositely in the runs, and adjustable means car-l ried by the conveyor and adapted to engage material in one run at a certain'depth and in the otherrun at thesame or a different depth.

8. In a drier, a covered passageway and means including flights'for moving material therethrough, a vapor discharge opening at the inlet end of the passageway, a hotl vaporl inlet adjacent the other end of the passageway, and means in the passageway adjacent the discharge end for directing the passage of vapor away from the discharge end to insure that the hot vapor lwill be moved in the trough in a direction opposite to the movement of material to be dried therein.

4. In a drier, an enclosed passageway having an inlet at one end anda discharge at the other, means for moving material continuously through the passageway, heating means adjacent thefeeding end of the passageway, a hotfvapor inlet adjacent the discharge endof the passageway, and a plurality of hinged doors at the discharge end yof the passageway engaged by sai-d moving means for preventing the passage of vapor.

passageway in the discharge direcing a series of longitudinallyA arranged drying pipes in the bottom thereof, yof means for moving material along said pipes and simultaneously. stirring the material in order to expose the heated material to the drying agent,

7. In a drier, the combination with a closed trough, of a conveyor adapted to moveand stir material in the trough, said conveyor having laterally adjustable flights 10 substantially as described. i

.WILLIAM E. HAMILTON; ERNEST Js BAGNALL. 

